Method of sealing the orifice of a metal tube

ABSTRACT

A method of sealing the orifice of a metal tube by: rotating the metal tube to be sealed and using a heat source to soften the orifice of the metal tube to be sealed, and then using a mold to mold the softened material of the metal tube, enabling an end wall, which can have any of a variety of shapes, to be formed integral with the metal tube to seal the orifice.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a method of sealing the orifice of a metal tube, and more particularly to such an orifice sealing method, which enables the orifice of a metal tube to be sealed by the material of the tube itself.

[0002]FIG. 1 illustrates the sealing of the orifice of a metal tube according to the prior art. According to this sealing design, a sealing plug 11 is attached to the orifice 10 of the tube 1, and then the connecting area between the tube land the sealing plug 11 are welded together by a welding torch. This orifice sealing procedure is complicated, and its sealing cost is high. After sealing, the sense of beauty of the tube is destroyed. During welding, bubbles may occur in the connecting area between the tube and the sealing plug, thereby causing the connecting area to leak. Further, the structural strength at the connecting area between the tube and the sealing plug is less strong, and tends to be broken. FIGS. 2 and 3 illustrate another orifice sealing method according to the prior art (Taiwan Patent No. 81216620, published on Feb. 11, 1993). According to this method, two vertically spaced ramming wheels 21 and 22 are rotated in reversed directions against the orifice 20 of the tube 1, causing the peripheral edge of the orifice 20 to be curved outwards toward the central axis of the tube 1, and therefore the orifice 20 of the tube 1 is sealed. After sealing, a small gap 23 is left at the center, and an internal stress is produced inside the protruding sealing end. Due to the existence of the internal stress, the protruding sealing end is less strong, and tends to be forced to break. Further, In order to close this small gap 23, a secondary sealing procedure must be performed.

SUMMARY OF THE INVENTION

[0003] The present invention provides an orifice sealing method, which eliminates the aforesaid drawbacks. According to the present invention, the orifice of the metal tube is softened by heat, and at the same time the end wall of the tube around the orifice is molded into a particular sealing structure to seal the orifice. The invention achieves the following advantages:

[0004] 1. No complicated procedure is necessary when sealing the orifice of the metal tube, and an integrated sealing structure of high structural strength can be quickly formed to seal the orifice of the metal tube.

[0005] 2. The end wall can be molded into any of a variety of shapes by means of the application of any of a variety of molds.

[0006] 3. The end wall can be processed into a rod member having an outer thread, a rounded head, or a neck for installation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 illustrates the sealing arrangement of the orifice of a metal tube according to the prior art.

[0008]FIG. 2 illustrates another orifice sealing arrangement according to the prior art (before sealing).

[0009]FIG. 3 shows the orifice of the metal tube sealed according to the sealing arrangement shown in FIG. 2.

[0010]FIG. 4 illustrates one orifice sealing arrangement according to the present invention.

[0011]FIG. 5 illustrates another orifice sealing arrangement according to the present invention.

[0012]FIG. 6 shows one sealing example of the present invention, where a screw rod is formed integral with the end of the metal tube.

[0013]FIG. 7 shows another sealing example of the present invention, where a rod with a rounded head is formed integral with the end of the metal tube.

[0014]FIG. 8 shows the rounded head of the rod at the end of the metal tube shown in FIG. 7 coupled to a coupling hole.

[0015]FIG. 9 shows still another sealing example of the present invention, where a rod with a neck is formed integral with the end of the metal tube.

[0016]FIG. 10 shows the rod at the end of the metal tube inserted through a through hole at an object, and a C-shaped clamp fastened to the neck at the rod.

[0017]FIG. 11 shows still another sealing example of the present invention, where a flat end wall is formed integral with the end of the metal tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] Referring to FIGS. 4 and 5, the method of sealing the orifice of a metal tube according to the present invention comprises the steps of: (1) rotating the metal tube 3 to be sealed, (2) using a heat source, for example, a welding torch A to soften the orifice 30 of the metal tube 3, and (3) using a mold B to mold the softened material of the metal tube 3, enabling an end wall 31 to be formed integral with the metal tube 3 to seal the orifice 30. The end wall 31 has a thickness greater than the wall thickness 32 of the metal tube 3. Therefore, the end wall 31 is strong enough to bear high pressure.

[0019] The end wall 31 can have any of a variety of shapes subject to the design of the mold B used. Figures from 6 through 11 show the end wall processed into different structures. In FIG. 6 shows the end wall processed into a rod 33 having an outer thread 330. FIG. 7 shows the end wall processed into a rod 33 having a rounded head 331 for coupling to a coupling hole at an object C. FIG. 9 shows the end wall processed into a rod 33 having a neck 332. FIG. 10 shows the rod 33 of the metal tube shown in FIG. 9 inserted through a through hole at an object, and a C-shaped clamp D fastened to the neck 332 at the rod 33. FIG. 11 shows the end wall 31 flattened.

[0020] After sealing of the orifice 30 of the metal tube 3, the end wall 31 may be treated different heat treatment, such as quenching, tempering, annealing, etc., to reinforce its structural strength. 

What the invention claimed is:
 1. A method of sealing the orifice of a metal tube comprising the steps of: (1) rotating the metal tube to be sealed; (2) using a heat source to soften the orifice of the metal tube to be sealed; (3) using a mold to mold the softened material of the metal tube, enabling an end wall to be formed integral with the metal tube to seal the orifice.
 2. The method of claim 1 wherein said end wall has a conical shape.
 3. The method of claim 1 wherein said end wall smoothly curves outwards.
 4. The method of claim 1 wherein said end wall is a planar wall.
 5. The method of claim 1 wherein said end wall is molded by said mold into a rod member.
 6. The method of claim 5 wherein said rod member has an outer thread.
 7. The method of claim 5 wherein said rod member has a rounded head.
 8. The method of claim 5 wherein said rod member has a neck. 